Throttle valve



March 17, 1931. J. H. DoRAN THROTTLE VALVE Filed May 23, 1929 Inventor: John H.Doran, bs fw/Wum His Attorneg.

Patented Mar. 17, 1931 UNITE rTA'ES recrear koI-"Flca `JOHN H. DORAN, F SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, .A CORPORATION OF NEW YORK THROTTLE 'VALVE AppIication filed Mayr'23, 1929. SeriaI No. 365,428.

The present invention relates to throttle valves and is intended more especially for use with elastic fluid turbines of large output operating under relatively heavy pressures.

Prior to putting such a turbine into service it is necessary to permit a. relatively small amount of fluid, such as steam, to enter the same in order to raise the temperature of the working parts to substantially that of their operating temperature and thereby avoid undue heat stresses when the load is applied, and also to gradually bring it up to normal running speed. This cannot be done with the main valve as Vit cannot kbe controlled with suicient accuracy for such small Hows of motive fluid. as'are' required. It is also necessary that the throttle valve be nearly balanced in order that it may be opened easily.

The object of myinvention is to improve the construction of throttle valves of the character referred to, and is vspecifically directed to the construction and arrangement of by-pass and valve means within the main valve which means is so arranged that `when lirst moved it admits fluid in a proper manner throughV a small by-pass to balance the main valve and thereafter opens a bypass of relatively large size to supply Huid to heat Vthe turbine and bring it upto running speed, preparatory to. putting it under load. v

For a consideration ofwhat I believe to be Vnovel and my invention, attention is directed to the accompanying description and the claim appended thereto. y

In the accompanying drawing which is illustrative of one embodiment of my invention, in Fig. 1 is shown a valve in vertical section, and Fig. 2is a detail view of a portion of the pilot valve.

1 indicates the :body of the valve having an inlet conduit 2 and an outlet conduitp. 4 indicates the upper head of the body which is provided with a packed central opening to receive the valve operating spindle 5. 1t is also provided with an extension 6 on its underside which forms a cylinder. 8 indicates the lower head ofthe body which is provided with a packed central opening to 'i 50 receive the lower end of the valve operating spindle. The portion of the body immediately above this head is provided with a cylinder 9, which acts as a part of a dashpot. 10 indicates the valve seat which is suitably beveled to receive the main valve.

VThe valve itself comprises a disc-like por` tion 11 which is adapted to engage the seat when in its closed position. Formed integral with the valve disc or secured thereto,

is a balancing piston member 12 which moves within the cylinder 6 and which is provided with a suitable packing ring. The parts are so arranged that the valve has a tendency to close when its operating mechanism is released. Situated at the upper end of the piston is bridge piece 13 by means of which the valve may be opened, aswill appear later.

' Below the valve disc is a. tubular extension auxiliary valve, which is a by-pass valve,

controls the How of steam from the inlet 2 to the outlet 3 when it is desired to admit steam in suthcient amount tothe turbine or other steam consuming apparatus for the purpose of warming it up andbringing it to normal speed preparatory to driving its load. For this purpose side opening ports 2() are provided above the valve disc and similar ports 21 below the valve disc. The upper end of the tubular member is provided with ashoulder 22 made in the form of a removable screw threaded nut and a seat 22a between which is located a valve in the form of a collar 23 on the spindle. ing the nut 22, the spindle 5 may be removed Jfrom the auXiliary tubular valve member 18. The upper end of the tubular member is also provided with vone or more small ports 24 through which steam can flow into and through the tubularmember when the collar 23, which forms a pilot valve, is raised from By unscrewthe lower shoulder on the member, which shoulder 'orms a valve seat. lNhere the spindle passes through the bridge 13 ample space is provided to permit steam to enter from the small port 7.

The valve may be actuated by any suitable means. The arrangement shown comprises a yoke 25 which is attachedto the upper side of the valve body and its upper end is provided with a sliding nut 26 surrounding the threaded part of the spindle which nut is prevented from turning by the key 27. At the top of the spindle is a hand wheel 28 by means of which the valve can be opened and closed at will. In order to provide for emergency operation the nut is supported on the lever 29. During normal operation the lever is held in its raised position by a pivoted latch 30. Secured to the pivot of the latch is a hand trip lever 31 by means of which the valve can be released and permitted to close7 this being done by an upward movement of the free end of the lever. The parts are normally held in the position shown by a lever 32, one arm of which rests on the latch and which is held in that position by the coiled spring 33 which is held under compression by the rod 34 having nuts on its outer end. One arm of this trip lever is connected by a rod 35 to a pivoted latch 36.Y Under normal conditions the latch 36 holds the spring 33 under compression with the result that the nut support- Y ing lever 29 is retained in the position shown. When the emergency governor operates it releases the latch 36 and the spring 33 operates to swing the lever 32 about its pivot and releases the lever which carries the sliding nut.

The operation of my improved valve is as follows: Assuming that the valves are seated with high pressure steam in the conduit 2 and low pressure steam in the conduit 3, there will be steam above the balance piston 12 due to leak past the piston rings and from the y port 7. The pilot valver23 being on its seat 22a will prevent the flow of steam from one side of the valve to the other. Assuming that it be desired to relieve the pressure on opposite sides of the Vvalve so that it may be more easily openedthe spindle 5 is raised yslightly by turning the hand-wheel 28, the

coupling 5a between the parts of the spindle permitting the upper part to turn while the lower part moves longitudinally. This ae. tion will permit the steam which has accumulated by leakage past the piston to pass from above the piston 12 through the port 2li and the center of the tubular member 18 and v main and second valves.

. the purpose of heating or initial starting,

the spindle 5 and the pilot valve 23 are raised to a point where the valve at the lower end of member 18 is raised from its seat 19. This permits a comparatively large amount of steam to flow from the port 2O through the main valve and port 21 into the conduit 3 and thence to the turbine. After the turbine has been properly heated the hand wheel 28 is rotated in the valve opening direction until the upper end ofthe tubular member 18 strikes the bridge piece 13 after which all of the valve parts move as a unit. In closing the valve the hand wheel is rotated in the opposite direction and the parts are screwed down until auxiliary valve 18 is seated, and thereafter pilot valve 23 is seated. For emergency operation the speed governor trips the latch 36 which releases the right hand end of the lever which supports the sliding nut and the slight preponderance,

of steam pressure on the upper side of the piston plus its weight causes the valve to close. The emergency mechanism is reset by turning the hand wheel in the valve closing direction until the lever 29 is raised to its,

latching position, after which the other parts are reset as shown in the figure.

It will be seen from my improved construction that a small by-pass is provided for balancing both the main valvey and also the large secondary or by-pass valve when it is desired to open them by hand and that the larger bypass is provided for supplying a considerable quantity of steam for heating or other purposes, that all three of the valves are operated successively by the same spindle without in any way affecting the automatic release mechanism, and that all of these advantages and desirable features are brought about by the inclusion within the main valve of a few very simple parts.

What I claim as new and desire to secure by Letters Patent of the United States is A throttle valve comprising a body having an inlet and an outlet, a main valve therein having a self-closing tendency, a piston and cylinder for substantially balancing 'the valve, a hollow body which unites the valve and piston, an inlet port in the body, a tubular member located within and guided by a wall of the hollow body, one end of which forms a tubular by-pass valve controlling the passage of fluid through the inlet port, a shoulder and a pilot valve seat located at the opposite end of the member, a port admitting fluid above the valve sea-t, a spindle concen-iV trically located within the member and eX- tending through it, a collar on the spindle, one side of whichl acts as a pilot valve, the other side engaging said shoulder when it is desired to open the tubular and main valves in succession, aI means secured to the balancing piston which is engaged by the shoulder during the opening movements of the valves, a tubular extension on the outletside of the main Valve, an outlet port therein, a, dash pot, the piston of which is secured to said extension, and a means for moving the spindle axially to open and close the valves sucoessively.

In Witness whereof, I have hereunto set my hand this 21st day of May, 1929.

JOI-IN H. DORAN. 

